random intermittent oil light?

[MattoB]

Welcome to Mud.

The two sensors/gauges are not connected; oil pressure gauge in the instrument cluster and oil level orange/yellow "idiot" light. There are no red oil pressure warning lights on the US spec FZJ80. Maybe your model is different??

Also normal for the orange/yellow low oil level light to come on intermittantly
as the oil level gets close to one quart low, then it will come on more frequently as the oil level continues to drop and finally stay solid when
you reach around 1-1/2 quarts low.

IME the oil level sensor float (?bakelite) can crack apart with age which may
give odd results depending on how much of the float has broken off.

Here's another source:

SENSOR, ENGINE OIL LEVEL 8949160060 | Toyota Parts | PartSouq

Quality parts for Toyota auto with fast delivery here! For a fast search using the part number 8949160060 - SENSOR, ENGINE OIL LEVEL

partsouq.com

Sorry my 100 is a 1HDFTE. I was getting the low oil light even though I had oil pressure and plenty of oil on the dipstick. Actually I had overfilled the oil at the last service. It would stand to reason that a turbo diesel would have a il pressure guage and low oil pressure warning light. I think the plastic sleeve on the pin the float travels on is the probably the real cause of the fault. The old one had definitely worn a notch in it. The new one was perfectly smooth. I hooked the old gauge up to a batterry and multimeter. When the float is all the way up the circuit is open and when it's all the way down the circuit is closed.